Self-limiting chemical vapor deposition and atomic layer deposition methods

ABSTRACT

Methods for depositing silicon on a semiconductor or metallic surface include cycling dosing of silane and chlorosilane precursors at a temperature between 50° C. and 300° C., and continuing cycling between three and twenty three cycles until the deposition self-limits via termination of surface sites with Si—H groups. Methods of layer formation include depositing a chlorosilane onto a substrate to form a first layer, wherein the substrate is selected from the group consisting of In x Ga 1-x As, In x Ga 1-x Sb, In x Ga 1-x N, SiGe, and Ge, wherein X is between 0.1 and 0.99. The methods may include pulsing a silane to form a silicon monolayer and cycling dosing of the chlorosilane and the silane. Layered compositions include a first layer selected from the group consisting of In x Ga 1-x As, In x Ga 1-x Sb, In x Ga 1-x N, SiGe, and Ge, wherein X is between 0.1 and 0.99, and a second layer, wherein the second layer comprises Si—H and Si—OH.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. patent application Ser. No.14/561,525, filed Dec. 5, 2014, which is herein incorporated byreference in its entirety, which claims priority to U.S. ProvisionalPatent Application Ser. No. 61/912,930, filed Dec. 6, 2013, which isherein incorporated by reference in its entirety.

FIELD

Embodiments of the present disclosure generally relate to deposition ofmaterials. Another field of the present disclosure is semi-conductordevice fabrication technology. Particular applications of the presentdisclosure include the formation of silicon layers.

BACKGROUND

A sub 400° C. ALD process for growing monolayers of Si on clean surfacesby alternating pulses of Si₂H₆ and SiCl₄ employed with the substratetemperature varied between 355°-385° C. The process is slow, with eachALD cycle taking several minutes and the desorption of the HCl(g)byproduct being slow below 400° C. Other processes include monolayersilicon ALD growth on Ge with use of alternating pulses of Si₂Cl₆ andatomic hydrogen, or Si₂Cl₆ and Si₂H₆, at undesirably high substratetemperatures of 400°-465° C.

Physical vapor deposition (PVD) of silicon for passivation of III-Vsurfaces has been reported, but requires a silicon multilayer as thesilicon is not ordered. Also, the PVD deposition of silicon is notcompatible with processing of three dimensional devices such as finFETson large semiconductor wafers.

SUMMARY

In one embodiment, a method for depositing silicon on a semiconductor ormetallic surface comprises cycling dosing of silane and chlorosilaneprecursors at a temperature between 50° C. and 300° C. and continuingcycling between three and twenty three cycles until the depositionself-limits via termination of surface sites with Si—H groups.

In another embodiment, a method of layer formation comprises depositinga chlorosilane onto a substrate to form a first layer, wherein thesubstrate is selected from the group consisting of In_(x)Ga_(1-x)As,In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between0.1 and 0.99. The method may include pulsing a silane to form a siliconmonolayer. The method may include cycling dosing of the chlorosilane andthe silane.

In another embodiment, a layered composition comprises a first layerselected from the group consisting of In_(x)Ga_(1-x)As,In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between0.1 and 0.99, and a second layer, wherein the second layer comprisesSi—H and Si—OH.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is overlaid XPS spectra illustrating the increase of the silicon2p3/2 peak and the decrease in the gallium 3p3/2 peak according to someembodiments of the present disclosure.

FIG. 2 is overlaid XPS spectra illustrating the increase of the silicon2p3/2 peak and the decrease in the gallium 3p3/2 peak according to someembodiments of the present disclosure.

DETAILED DESCRIPTION

In one embodiment, a method for depositing silicon on a semiconductor ormetallic surface comprises cycling dosing of silane and chlorosilaneprecursors at a temperature between 50° C. and 300° C. and continuingcycling between three and twenty three cycles until the depositionself-limits via termination of surface sites with Si—H groups.

In another embodiment, a method of layer formation comprises depositinga chlorosilane onto a substrate to form a first layer, wherein thesubstrate is selected from the group consisting of In_(x)Ga_(1-x)As,In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between0.1 and 0.99. The method may include pulsing a silane to form a siliconmonolayer. The method may include cycling dosing of the chlorosilane andthe silane.

In another embodiment, a layered composition comprises a first layerselected from the group consisting of In_(x)Ga_(1-x)As,In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between0.1 and 0.99, and a second layer, wherein the second layer comprisesSi—H and Si—OH.

Embodiments of the present disclosure may provide self-limiting andsaturating atomic layer deposition (ALD) and self-limiting andsaturating chemical vapor deposition (CVD) of a silicon seed layer on avariety of non-silicon layer surfaces. Embodiments of the presentdisclosure may include depositing a silicon seed layer on substrates ofvarying alloy compositions (e.g. indium gallium arsenide, indium galliumantiminide, indium gallium nitride, and silicon-germanium), as well asgermanium and metallic substrates.

Embodiments of the present disclosure provide low temperature siliconALD and can use different substrates. Embodiments provide a comparabledrop in substrate temperature to 250° C. or less in addition toproviding self-limiting and saturating ALD growth.

Artisans have failed, to the knowledge of the present inventors, toprovide self-limiting and saturating silicon CVD on non-silicon surfacesdespite studies and reports in the literature of temperature ranges atwhich hydrogen desorption occurs from similar applicable substrates ofSi, Ge, and GaAs. The silane precursor self-limiting CVD processproduces saturation when all surface sites are terminated by Si—Hgroups. Thus, desorption of H₂(g) from substrate surface sites may occuruntil all surface sites become terminated by Si—H. Increase of substratetemperature to 400° C. leads to continued ALD silicon growth on top ofthe self-limiting ALD silicon seed layer or on top of the saturatedself-limited CVD silicon seed layer.

For oxide deposition, metal contact deposition, surfacefunctionalization, surface passivation, and oxide nucleation, methods ofthe present disclosure provide advantages compared to typical currentsemiconductor and metal substrate surface preparation and controlledgrowth methods.

Methods of the present disclosure may provide for improved semiconductorand metal substrate surface preparation and controlled growth methods.Functionalization creates a surface that is reactive to ALD precursors.Passivation forms a monolayer that leaves the Fermi level unpinned. Themonolayer nucleation is the initial layer of ALD deposition. The processis low temperature. In one embodiment, preparation, functionalization,passivation and ALD deposition is performed at 250° C. Certain surfacesand substrates will permit lower temperatures. Substrates thatrecombinatively desorb H₂ at lower temperatures, e.g., 150° C., permituse of lower temperatures. Examples include InGaAs and InAs.

Present silicon saturating and self-limiting ALD and CVD processes ofthe present disclosure achieve functionalization, passivation andmonolayer nucleation at 250° C. (and lower for some substrates), whichis much lower temperature, on both metallic and semiconductorsubstrates, than comparable silicon ALD procedures reported inliterature. The self-limiting and saturating silicon CVD process at 250°C. is advantageous from a device fabrication standpoint compared toexisting silicon ALD processes that are at significantly highertemperature (above 350° C.) and provide for continuous growth of siliconon silicon and is not self-limiting. A unique strong bonding of siliconto all crystal faces of In_(x)Ga_(1-x)As, In_(x)Ga_(1-x)Sb,In_(x)Ga_(1-x)N, SiGe, and Ge should enable transfer of the danglingbonds from the substrate to silicon, and silicon is readily hydrogenpassivated even by molecular H₂ due to the uniquely strong Si—H bonds.The monolayer of —OH may be ideal for nucleating almost any metal ALDprecursor.

The ability to passivate metallic surfaces provides additionalapplications beyond semiconductor device fabrication. For example,methods of the present disclosure can provide a surface protectionagainst oxidation on metallic surfaces.

The present disclosure provides, for example, self-limiting andsaturating atomic layer deposition (ALD) and self-limiting andsaturating chemical vapor deposition (CVD) of a silicon seed layer onindium gallium arsenide (InGaAs), indium gallium antiminide (InGaSb),indium gallium nitride (InGaN), and silicon-germanium (SiGe) substratesof varying alloy compositions, as well as germanium and metallicsubstrates. Embodiments of the present disclosure also provide aprocedure for ALD silicon on top of the self-limiting ALD silicon seedlayer or on top of the saturated self-limited CVD silicon seed layer forcontinued growth of silicon.

A silicon monolayer deposited as described herein can serve severalpurposes. (1) The dangling bonds of the substrate will be transferred tosilicon, which are then passivated by hydrogen, leaving the surfaceelectrically passivated. (2) The saturated monolayer of silicon with Hpassivation will serve to protect the semiconductor or metallicsubstrate from oxidation. (3) The silicon monolayer with possible Htermination (e.g. Si—H) can also be employed for deposition of gateoxide through functionalization by an oxidant such as HOOH(g), in orderto create an Si—OH layer which would react with nearly any ALD precursorthereby eliminating the need for metal precursor nucleation (for examplewith trimethyl aluminum predosing) decreasing EOT and lowering bordertrap density and fixed charge associated with interfacial layers or evendirect bonding of oxide to nonsilicon semiconductors. The same procedurecan be used for other crystallographic faces such asIn_(x)Ga_(1-x)As(110), In_(x)Ga_(1-x)Sb(110), In_(x)Ga_(1-x)N(110),SiGe(110), and Ge(110). Some ALD precursors such as those containing Oor OH groups may directly react with the Si—H termination. (4) Thesilicon monolayer or silicon monolayer with additional oxide ALD can beemployed for metal contact formation.

Experiments of the present disclosure will be understood by artisans inview of the general knowledge in the art and the description thatfollows to illustrate broader features of some embodiments of thepresent disclosure.

The experiments showed self-limiting ALD of silicon on semiconductor andmetal surface. Dosing parameters for near saturation coverage of siliconon clean InGaAs surface through cyclic dosing of Si₂Cl₆ and Si₃H₈ wereshown. Scanning Tunneling Microscopy (STM) and X-Ray PhotoelectronSpectroscopy (XPS) measurements were performed to investigate surfacebonding configurations and electronic structures ofSi/InGaAs(001)-(2×4). Thermal annealing measurements were also performedduring this time to demonstrate thermal stability of the surface.

The experiments also show self-limiting CVD of silicon on semiconductorand metal surfaces through dosing of Si₃Ha. Dosing parameters weredetermined for near saturation coverage of silicon on clean InGaAssurface. STM and XPS measurements were used to investigate surfacebonding configurations and electronic structures ofsilicon/InGaAs(001)-(2×4). Thermal annealing measurements were alsoperformed during this time to demonstrate thermal stability of thesurface.

One embodiment includes a self-limiting atomic layer depositionprocedure based upon the saturation of the substrate semiconductor ormetallic surface sites through a surface termination with Si—H and Si—Clgroups by cyclic dosing of silane and chlorosilane precursors at 250° C.Silane precursors include: SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, Si₅H₁₂ andchlorosilane precursors include: SiCl₄, Si₂Cl₆, Si₃Cl₈. Once all surfacesites are terminated with Si—H and Si—Cl groups, the reaction becomesself-terminating, as hydrogen and chlorine bond to silicon stronger thanother semiconductor or metallic materials. The self-limiting andsaturating chemical vapor deposition procedure is based upon thesaturation of the substrate semiconductor or metallic surface sitesthrough a surface termination with Si—H groups by dosing a silaneprecursor at 250° C. Once surface sites are terminated with Si—H groups,the reaction becomes self-terminating, as hydrogen bonds to siliconstronger than other semiconductor or metallic materials. Further silicongrowth can occur on either the self-limiting atomic layer deposition orchemical vapor deposition saturated surfaces by raising the temperatureto 400° C. The H₂(g) and HCl(g) desorption product occurs only slowlybelow this temperature at the point of surface saturation.

The self-limiting atomic layer deposition procedure in an experiment isdiscussed next. A decapped In_(0.53)Ga_(0.47)As(001)-(2×4) surface wasdosed with 1 MegaLangmuir of Si₂Cl₆ followed by 1 MegaLangmuir of Si₃H₈at a sample temperature of 250° C. This procedure constitutes onecomplete self-limiting and saturating ALD cycle. After three cycles, anX-ray photoelectron spectroscopy (XPS) spectrum is taken of the surfacewith a non-monochromatic aluminum channel X-ray flood source system at aglancing angle of 30° to produce surface sensitive spectra. The XPSspectra were also recorded following 13 and 23 total self-limiting andsaturating ALD cycles. FIG. 1 shows the increase of the silicon 2p3/2peak at 100 eV and the decrease in the gallium 3p3/2 peak at 105 eV, asindicated by the arrows for all three spectra as well as the spectra ofthe clean decapped surface for comparison.

As shown in FIG. 1: Non-monochromatic aluminum channel X-ray floodsource system spectra for clean decapped In_(0.53)Ga_(0.47)As(001)-(2×4)surface (100), In_(0.53)Ga_(0.47)As(001)-(2×4) surface following 3 ALDcycles at 250° C. (102), In_(0.53)Ga_(0.47)As(001)-(2×4) surfacefollowing 13 ALD cycles at 250° C. (104), andIn_(0.53)Ga_(0.47)As(001)-(2×4) surface following 23 ALD cycles 250° C.(106). The spectra are shown of the Ga 3p3/2 and Si 2p3/2 peaks. Asshown in Table 1 and FIG. 1 (by, for example, the Ga 3p3/2 peak at 105eV of 100, 102, 104 and 106) near saturation of silicon onIn_(0.53)Ga_(0.47)As(001)-(2×4) surface is reached after 13self-limiting ALD cycles at 250° C. Full saturation may involve about 50pulses or a different operating temperature; since the kinetics arelikely desorption limited there are a variety of pulse times,desorption/purge times, and processing temperature which will suffice.

The raw counts corrected by Schofield photoionization cross sectionalrelative sensitivity factors are recorded for doublet peak pairs of As2p, Ga 2p, In 3d, Si 2p, Cl 2p for the clean decappedIn_(0.53)Ga_(0.47)As(001)-(2×4) surface (100) as well as the 3, 13, and23 ALD cycle dosed surfaces at sample temperature 250° C. (102, 104 and106, respectively) and are shown in Table 1.

TABLE 1 Non-monochromatic aluminum channel X-ray flood source system rawcounts corrected by Schofield photoionization cross sectional relativesensitivity factors for clean decapped In_(0.53)Ga_(0.47)As(001)-(2 × 4)surface (100), In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 3 ALDcycles at 250° C. (102), In_(0.53)Ga_(0.47)As(001)-(2 × 4) surfacefollowing 13 ALD cycles at 250° C. (104), andIn_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 23 ALD cycles 250°C. (106). Surface As 2p Ga 2p In 3d Si 2p Cl 2p Clean decapped 184.8155.2 689.9 0.0 0.0 In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface (100) 3ALD cycles at 250° C. (102) 158.2 112.4 483.5 509.9 581.3 13 ALD cyclesat 250° C. (104) 115.6 72.2 242.4 665.6 576.3 23 ALD cycles at 250° C.(106) 90.5 57.6 351.3 714.7 544.2

The raw counts corrected by Schofield photoionization cross sectionalrelative sensitivity factors are recorded and listed in Table 2 asrelative atomic ratios compared to the total As 3d peak. All peaksratios tabulated in Table 2 are from comparable low binding energies,including: Ga 3d, In 3d, Si 2p, Cl 2p, and Ta 4d total peak values forboth doublet peak pairs, as well as the O 1s, C 1s peaks. Ratios arelisted for the clean decapped In_(0.53)Ga_(0.47)As(001)-(2×4) surface(100) as well as the 3, 13, and 23 ALD cycle dosed surfaces at sampletemperature 250° C. (102, 104 and 106, respectively). As shown in Table2 and FIG. 1 (by, for example, the Ga 3p3/2 peak at 105 eV of 100, 102,104 and 106) near saturation of silicon onIn_(0.53)Ga_(0.47)As(001)-(2×4) surface is reached after 13self-limiting ALD cycles at 250° C. Full saturation may involve about 50pulses or a different operating temperature; since the kinetics arelikely desorption limited there are a variety of pulse times,desorption/purge times, and processing temperature which will suffice.

TABLE 2 Non-monochromatic aluminum channel X-ray flood source system rawcounts corrected by Schofield photoionization cross sectional relativesensitivity factors and listed as relative atomic ratios compared to thetotal As 3d peak: All spin orbit split peaks include peak counts fromboth doublet pair peaks. Ratio values are listed for clean decappedIn_(0.53)Ga_(0.47)As(001)-(2 × 4) surface (100),In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 3 ALD cycles at 250°C. (102), In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 13 ALDcycles at 250° C. (104), and In_(0.53)Ga_(0.47)As(001)-(2 × 4) surfacefollowing 23 ALD cycles 250° C. (106). Surface As 3d Ga 2p In 3d Si 2pCl 2p O 1s C 1s Ta 4d Clean decapped 1.00 0.90 0.56 0.00 0.00 0.03 0.130.29 In_(0.53)Ga_(0.47)As(001)- (2 × 4) surface (100) 3 ALD cycles at250° C. 1.00 0.78 0.37 0.39 0.44 0.32 0.38 0.35 (102) 13 ALD cycles at250° C. 1.00 0.80 0.19 0.52 0.45 0.53 0.50 0.33 (104) 23 ALD cycles at250° C. 1.00 0.81 0.30 0.62 0.47 0.51 0.62 0.34 (106)

The filled-state STM image may be obtained ofIn_(0.53)Ga_(0.47)As(001)-(2×4) surface following 23 self-limiting andsaturating ALD cycles of 1 MegaLangmuir of Si₂Cl₆ followed by 1MegaLangmuir of Si₃H₈ at a sample temperature of 250° C. as compared tothe clean decapped In_(0.53)Ga_(0.47)As(001)-(2×4) surface. The dosedsurface contains high atomic surface order and the surface should beterminated by Si—H, leaving the surface Fermi level unpinned.

The self-limiting and saturating CVD procedure may include a decappedIn_(0.53)Ga_(0.47)As(001)-(2×4) surface dosed with 1 MegaLangmuir ofSi₃H₈ at a sample temperature of 250° C. This procedure constitutes onecomplete self-limiting and saturating CVD cycle. After three cycles, anX-ray photoelectron spectroscopy (XPS) spectrum is taken of the surfacewith a non-monochromatic aluminum channel X-ray flood source system at aglancing angle of 30° to produce surface sensitive spectra. The XPSspectra were also recorded following 13 total self-limiting andsaturating CVD cycles. FIG. 2 shows the increase of the silicon 2p3/2peak at 100 eV and the decrease in the gallium 3p3/2 peak at 105 eV, asindicated by the arrows for both spectra as well as the spectra of theclean decapped surface for comparison.

As shown in FIG. 2: Non-monochromatic aluminum channel X-ray floodsource system spectra for clean decapped In_(0.53)Ga_(0.47)As(001)-(2×4)surface (200), In_(0.53)Ga_(0.47)As(001)-(2×4) surface following 3 CVDcycles at 250° C. (202), and In_(0.53)Ga_(0.47)As(001)-(2×4) surfacefollowing 13 CVD cycles at 250° C. (204). The spectra are shown of theGa 3p3/2 peaks at 105 eV and Si 2p3/2 peaks at 100 eV.

The raw counts corrected by Schofield photoionization cross sectionalrelative sensitivity factors are recorded for doublet peak pairs of As2p, Ga 2p, In 3d, Si 2p, Cl 2p for the clean decappedIn_(0.53)Ga_(0.47)As(001)-(2×4) surface (200) as well as the 3 and 13CVD cycle dosed surfaces at sample temperature 250° C. (202 and 204,respectively) and are shown in Table 3. The Ga 3p3/2 peak continues todiminish with 13 cycles (204) and near saturation of silicon onIn_(0.53)Ga_(0.47)As(001)-(2×4) surface is reached after 13self-limiting and saturating CVD cycles at 250° C. (204). H₂ desorptionis close to zero at 250° C. on silicon.

TABLE 3 Non-monochromatic aluminum channel X-ray flood source system rawcounts corrected by Schofield photoionization cross sectional relativesensitivity factors for clean decapped In_(0.53)Ga_(0.47)As(001)-(2 × 4)surface (200), In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 3 CVDcycles at 250° C. (202), and In_(0.53)Ga_(0.47)As(001)-(2 × 4) surfacefollowing 13 CVD cycles at 250° C. (204). Surface As 2p Ga 2p In 3d Si2p Clean decapped 213.80 174.90 699.40 0.00 In_(0.53)Ga_(0.47)As(001)-(2× 4) surface (200) 3 ALD cycles at 250° C. (202) 130.10 119.40 545.40320.10 13 ALD cycles at 250° C. (204) 111.50 97.10 472.40 603.10

The self-limiting and saturating CVD procedure includes a decappedIn_(0.53)Ga_(0.47)As(001)-(2×4) surface dosed with 1 MegaLangmuir ofSi₃H₈ at a sample temperature of 250° C. This procedure constitutes onecomplete self-limiting and saturating CVD cycle. After three cycles, anXPS spectrum is taken of the surface with a non-monochromatic aluminumchannel X-ray flood source system at a glancing angle of 30° to producesurface sensitive spectra. The XPS spectra were also recorded following13 total self-limiting and saturating CVD cycles. FIG. 2 shows theincrease of the silicon 2p3/2 peak at 100 eV and the decrease in thegallium 3p3/2 peak at 105 eV, as indicated by the arrows for bothspectra as well as the spectra of the clean decapped surface forcomparison.

The raw counts corrected by Schofield photoionization cross sectionalrelative sensitivity factors are recorded and listed in Table 4 asrelative atomic ratios compared to the total As 3d peak. All peaksratios tabulated in Table 4 are from comparable low binding energies,including: Ga 3d, In 3d, Si 2p, Cl 2p, and Ta 4d total peak values forboth doublet peak pairs, as well as the O 1s, C 1s peaks. Ratios arelisted for the clean decapped In_(0.53)Ga_(0.47)As(001)-(2×4) surface(200) as well as for the 3 and 13 self-limiting and saturating CVD cycledosed surfaces at sample temperature 250° C. (202 and 204,respectively). As shown in Table 4 and FIG. 2 (by, for example, the Ga3p3/2 peak at 105 eV of 200, 202, and 204) near saturation of silicon onIn_(0.53)Ga_(0.47)As(001)-(2×4) surface is reached after 13 CVD cyclesat 250° C. In some embodiments, longer doses of Si₃Hs or 25+ cycles or adifferent operating temperature may be used; since the kinetics arelikely desorption limited there are a variety of pulse times,desorption/purge times, and processing temperature which will suffice.

TABLE 4 Non-monochromatic aluminum channel X-ray flood source system rawcounts corrected by Schofield photoionization cross sectional relativesensitivity factors and listed as relative atomic ratios compare to thetotal As 3d peak. All spin orbit split peaks include peak counts fromboth doublet pair peaks. Ratio values are listed for clean decappedIn_(0.53)Ga_(0.47)As(001)-(2 × 4) surface (200),In_(0.53)Ga_(0.47)As(001)-(2 × 4) surface following 3 self-limiting andsaturating CVD cycles at 250° C. (202), and In_(0.53)Ga_(0.47)As(001)-(2× 4) surface following 13 self-limiting and saturating CVD cycles at250° C. (204). Surface As 3d Ga 2p In 3d Si 2p Cl 2p O 1s C 1s Ta 4dClean decapped 1.00 0.98 0.61 0.00 0.00 0.66 0.57 0.38In_(0.53)Ga_(0.47)As(001)- (2 × 4) surface (200) 3 ALD cycles at 250° C.1.00 1.01 0.53 0.31 0.00 0.10 0.37 0.38 (202) 13 ALD cycles at 250° C.1.00 0.78 0.46 0.58 0.00 0.63 0.61 0.32 (204)

Many applications will be apparent to artisans from the abovediscussion. Particular applications include that the CVD or ALDdeposited silicon monolayer is applicable for use as a semiconductor andmetallic surface protection layer from unwanted oxidation. Thisapplication may serve useful during deposition and processing of gatestacks on FinFETs for MOSFETs. Embodiments of the present disclosure mayprovide surface termination by Si—H groups followed by functionalizationwith an oxidant, creating an Si—OH layer, which can be performed priorto oxide gate deposition and source drain contact formation. The sameprocess can be used for a monolayer oxide on unpinning of source/draincontacts on MOSFETs which is critical for SiGe. The same process can beused in flash memory where thin high-k oxides are needed for low voltageoperation.

While specific embodiments of the present disclosure have been shown anddescribed, it should be understood that other modifications,substitutions and alternatives are apparent to one of ordinary skill inthe art. Such modifications, substitutions and alternatives can be madewithout departing from the spirit and scope of the present disclosure,which should be determined from the appended claims.

Various features of the present disclosure are set forth in the appendedclaims.

We claim:
 1. A method for depositing silicon on a semiconductor or metallic surface, the method comprising: cycling dosing of silane and chlorosilane precursors at a temperature between 50° C. and 300° C.; and continuing cycling between three and twenty three cycles or until the deposition self-limits via termination of surface sites with Si—H groups.
 2. The method of claim 1, wherein the low temperature is at or below 250° C. and the surface is the surface of a substrate of one of In_(x)Ga_(1-x)As, In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, Ge and a metallic substrate.
 3. The method of claim 1, wherein the low temperature is at or below 150° C. and the surface is the surface of a substrate that recombinatively desorbs H₂ at or below 150° C.
 4. The method of claim 1, wherein the silane precursor is one of SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, and Si₅H₁₂.
 5. The method of claim 1, wherein the chlorosilane precursor is one of SiCl₄, Si₂Cl₆, and Si₃Cl₈.
 6. A method of layer formation comprising: depositing a chlorosilane onto a substrate to form a first layer, wherein the substrate is selected from the group consisting of In_(x)Ga_(1-x)As, In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between 0.1 and 0.99; pulsing a silane to form a silicon monolayer on the first layer; cycling dosing of the chlorosilane and the silane; and after self-termination, raising the temperature and depositing additional silicon.
 7. The method of claim 6, further comprising functionalizing the silicon monolayer with an oxidant.
 8. The method of claim 6, wherein the cycling dosing of the chlorosilane and the silane is performed within a range of 50° C. to 300° C.
 9. The method of claim 6, wherein the layer has a surface that recombinatively desorbs H₂ at or below 150° C.
 10. The method of claim 6, wherein the silane precursor is SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, or Si₅H₁₂.
 11. The method of claim 6, wherein the chlorosilane precursor is SiCl₄, Si₂Cl₆, or Si₃Cl₈.
 12. A layered composition comprising: a first layer selected from the group consisting of In_(x)Ga_(1-x)As, In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, and Ge, wherein X is between 0.1 and 0.99; and a second layer, wherein the second layer comprises Si—H and Si—OH.
 13. A method for depositing silicon on a semiconductor or metallic surface, the method comprising: cycling dosing of silane and chlorosilane precursors at a temperature between 50° C. and 300° C.; and continuing cycling until the deposition self-limits via termination of surface sites with Si—H groups.
 14. The method of claim 13, wherein the low temperature is at or below 250° C. and the surface is the surface of a substrate of one of In_(x)Ga_(1-x)As, In_(x)Ga_(1-x)Sb, In_(x)Ga_(1-x)N, SiGe, Ge and a metallic substrate.
 15. The method of claim 13, wherein the low temperature is at or below 150° C. and the surface is the surface of a substrate that recombinatively desorbs H₂ at or below 150° C.
 16. The method of claim 13, wherein the silane precursor is one of SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, and Si₅H₁₂.
 17. The method of claim 13, wherein the chlorosilane precursor is one of SiCl₄, Si₂Cl₆, and Si₃Cl₈.
 18. The method of claim 13, further comprising, after self-termination, raising the temperature and depositing additional silicon. 